| 摘要: |
| 以往研究表明, 涌浪存在时, 近海面大气边界层内Monin–Obukhov相似性理论(Monin–Obukhov Similar Theory, MOST)将会失效, 风廓线模型的建立需要考虑波致应力的影响。基于此, 本文首先研究了包含涌浪影响的Ekman模型和常通量层模型求解的风廓线。结果表明: 两种模型估算的风廓线均对涌浪的波衰减率系数cβ有较高的依赖性, 在cβ<–50时, 模型求解的风廓线均出现近海面风速极大值, 但科氏力对近海面风廓线的影响可以忽略。在不同的大气层结下, 分析发现海浪边界层(直接受波浪影响的区域)内风速明显小于海浪边界层之上MOST廓线在相同高度的外推值, 体现了涌浪引起明显的剪切增强。通过对比分析广东省茂名市附近海上观测平台的实测数据发现, 在涌浪存在时, MOST普遍无法描述风廓线; 统计分析表明常通量层模型估算的风廓线在8 m处的风速与实测数据高度一致。考虑以往研究基本局限于中性大气层结条件, 而涌浪经常显著影响着浮力作用明显的中低风速条件, 我们的研究将有助于理解不同大气层结条件下涌浪对风廓线的影响。 |
| 关键词: MOST 涌浪 波致应力 海浪边界层 层结 |
| DOI：10.11759/hykx20230427001 |
| 分类号:P731 |
| 基金项目:国家自然科学基金项目(41830533) |
|
| Influence of swell on the wind profile in atmospheric boundary layer |
|
ZHANG Yuhao, SONG Jinbao, LIU Changlong
|
|
Ocean College, Zhejiang University, Zhoushan 316000, China
|
| Abstract: |
| Previous studies have shown that the Monin–Obukhov similarity theory (MOST) in the atmospheric boundary layer near the sea surface becomes invalid when a swell occurs, and the establishment of wind profile models needs to consider the influence of wave-induced stress. Based on this observation, this article first studied the wind profiles generated using the Ekman and constant flux layer models, which include the influence of swells. The results indicate that the wind profiles estimated by both models show a high dependence on the wave decay rate coefficient cβ of a swell. When cβ < −50, both the wind profiles show maximum wind speeds near the sea surface; however, the influence of Coriolis force on the wind profile near the sea surface can be ignored. Under various atmospheric stratification conditions, the analysis shows that the wind speed in the wave boundary layer (the area directly affected by waves) was significantly lower than the extrapolated value of the MOST profile above the wave boundary layer at the same height, reflecting the obvious shear enhancement caused by swells. On comparing and analyzing the measured data from offshore observation platforms near Maoming City, Guangdong Province, it was found that in the presence of a swell, MOST is generally unable to describe wind profiles. Statistical analysis shows that the wind speed estimated by the constant flux layer model at 8 m is highly consistent with the measured data. Considering that previous studies have been limited to neutral atmospheric stratification conditions and that swells often significantly affect low and medium wind speed conditions with an obvious buoyancy effect, our research will help explain the impact of swells on wind profiles under various atmospheric conditions. |
| Key words: MOST swell wave-induced stress wave boundary layer stratification |
